In the thesis, an LED driver circuit that is applied in low power lighting LED with constant output current and Power Factor Correction (PFC) is presented. The insulated Flyback converter is used for the LED driver. Power Factor Correction is realized with both the method of Voltage Follower Approach Control under Discontinuous Conduction Mode and the method of Boundary Conduction Control under Boundary Conduction Mode. Compared with Voltage Follower Approach Control, Boundary Conduction Control needs only output current feedback. Moreover, it possesses lesser magnetize inductance current, lesser electrical stress of elements, more flexible choice of elements specification, smaller output current ripples, and higher power factor under light load. The circuit design is expounded, and verified by IsSpice simulation and experiment result.

LCModel, which is performed on Linux, has been widely used for quantitative analysis of MRS. Its interface, LCMgui, converts MRS data of various formats to RAW file for LCModel analysis automatically. In this work, we had a web-based MRS analysis tool for GE MRS, GE MRS with Phase-Array and GE 2D-MRSI and improve the capability of web-based MRS analysis tool for GE 3D-MRSI, Siemens MRS/MRSI, and Philips MRS/MRSI. Meanwhile, T2 correction has been involved in the absolute quantification with LCModel. With the same echo-time, the different T2 value of each metabolite results in different degree of signal decay. In order to correct and make absolute concentrations more accurate, we exploit a factor to correct effect of different T2. Two groups of MRS data (TE = 35 and 272 ms) have been studied for comparison.

<p>This thesis reports the methods to simulate flows withcomplex boundary such as orifice flow. The method is forgeneral purposes so that it has been tested on different flowsincluding orifice flow. Also it contains a chapter about theexperiment of orifice flow.</p><p>Higher-order precision interpolation schemes are used inumerical simulation to improve prediction at acceptable gridrefinement. Because higher-order schemes cause instability inconvection-diffusion problems or involve a large computationalkernel, they are implemented with deferred correction method. Alower-order scheme such as upwind numerical scheme is used tomake preliminary guess. A deferred (defect) correction term isadded to maintain precision. This avoids the conflict betweenprecision order and implementation difficulty. The authorproposes a shifting between upwind scheme and centraldifference scheme for the preliminary guess. This has beenproven to improve convergence while higher order schemes havewider range of stability.</p><p>Non-orthogonal grid is a necessity for complex flow. Usuallyone can map coordinate of such a grid to a transformed domainwhere the grid is regular. The cost is that differentialequations get much more complex form. If calculated directly innon-orthogonal grid, the equations keep simple forms. However,it is difficult to make interpolation in a non-orthogonal grid.Three methods can be used: local correction, shape function andcurvilinear interpolation. The local correction method cannotinsure second-order precision. The shape function method uses alarge computational molecule. The curvilinear interpolationthis author proposes imports the advantage of coordinatetransformation method: easy to do interpolation. A coordinatesystem staggered half control volume used in the coordinatetransformation method is used as accessory to deriveinterpolation schemes. The calculation in physical domain withnon-orthogonal grid becomes as easy as that in a Cartesianorthogonal grid.</p><p>The author applies this method to calculate turbulentorifice flow. The usual under-prediction of eddy length isimproved with the ULTRA-QUICK scheme to reflect the highgradients in orifice flow.</p><p>In the last chapter, the author quantifies hydraulicabruptness to describe orifice geometry. The abruptness canhelp engineers to interpolate existing data to a new orifice,which saves detailed experiments</p>

La simulation numérique de correction chirurgicale de la scoliose peut apporter une aide précieuse à la planification d'une stratégie optimale pour un patient donné. Au cours des études précédentes menées au Laboratoire de Biomécanique, un premier modèle a été développé, et la faisabilité d'une telle simulation numérique personnalisée de chirurgie a été démontrée. Toutefois, l'extrême complexité et l'opérateurdépendance de ce modèle représentent un frein à son utilisation dans un cadre clinique. L'objectif de notre travail est, d'une part, de reprendre cette modélisation afin d'en améliorer deux éléments clefs pour une future utilisation clinique: l'automatisation de la personnalisation des propriétés mécaniques, et la robustesse (stabilité numérique et opérateur-indépendance) de la simulation de chirurgie. D'autre part, la modélisation de différents cas cliniques vise à évaluer la pertinence du modèle, et à mieux comprendre les mécanismes de correction. L'identification des propriétés mécaniques du rachis à partir de données in vivo (test clinique d'inclinaison latérale ou "bending"), a été automatisée en développant un algorithme d'optimisation guidée par de la connaissance a priori. La précision de cet outil a été évaluée sur des données in vivo issues des dossiers de trente patients scoliotiques. La simulation de chirurgie de correction de la scoliose a été rendue stable et opérateur-indépendante pour deux techniques différentes: par rotation de tige - instrumentation Cotrel- Dubousset ou CD - et par cintrage in situ ou CIS. En particulier, un algorithme spécifique définit et simule les séquences de cintrage in situ en accord avec l'expertise clinique. La cohérence de la simulation de chirurgie a été évaluée, tant au regard des données post-opératoires in vivo (issues des dossiers de vingt et dix patients scoliotiques pour les chirurgies respectives CD et CIS) que des mouvements vertébraux en per-opératoire (à partir de la littérature). Enfin, de multiples alternatives chirurgicales ont été envisagées, et différents concepts de correction ont été analysés sur le plan biomécanique. Notre travail ouvre des perspectives concrètes vers une utilisation en clinique de l'outil de simulation numérique personnalisée de chirurgie pour aider à la compréhension des mécanismes de correction, voire à la planification du geste chirurgical.

The purpose of this study was to investigate to what extent written corrective feedback (WCF) is a good way to treat errors that L2 (second language) pupils make and if they attend to the comments in future written assignments. WCF is the most used response on written assignments. Some research takes the perspective that it is fruitful (Chandler 2003, Ferris 2003) while other research argues that it is inefficient and unnecessary (e.g.Truscott 1996, 1999). This study presents the findings of a survey on the topic which was conducted at a small school in the south east of Sweden. A comparison between previous research and the findings of the present survey is made and the conclusion from this is that there are limitations in the efficacy of WCF and the results suggest that the type of feedback and how it is delivered are important. It is also likely to be beneficial that pupils revise their texts in order to improve in writing English.

In this study, the interaction energies between aromatic organic molecules (AOMs) and cellulose are explored using density functional theory (DFT) through the software SIESTA and the exchange-correlational functional VDW-DRSLL. Three AOMs will be modelled: benzene, benzamide and benzoic acid. Firstly, the interaction energies of the dimers of the AOMs are determined. Then, the obtained interaction energies of the cellulose-AOM complexes are compared to the former in order to decide which interaction is stronger. It is found that the studied AOMs are more likely to interact with cellulose than with another identical monomer; benzamide has the highest propensity to interact, followed by benzoic acid and benzene. Furthermore, for all interaction energy calculations a counterpoise correction term will be introduced as an addition to the SIESTA optimisation and it will be shown that without this correction the acquired energy minima will deviate significantly from accepted values from previous studies.

In the context of the SERVIR-Africa project, the SERVIR Arizona Team is developing streamflow forecast systems on African basins using Satellite Precipitation Products (SPP) to drive the models. These products have errors that need to be addressed before using them to drive hydrologic models. An analysis of the errors of the Satellite Precipitation Products TMPA-3B42RT, CMORPH, and PERSIANN over Africa is presented, followed by bias correction and error reduction methods to improve the remote sensed estimates. The GPCP 1-degree-day reanalysis product was used as the rainfall truth dataset. The Bias Correction Spatial Downscaling (BCSD) method developed by Wood et al., was used successfully to reduce the errors of SPP. The original and bias corrected estimates from the three SPP are used to calibrate and simulate three catchments of the Senegal River basin using HYMOD, finding that the use of bias corrected estimates produces a significant improvement in streamflow simulation.

The aim of this research is to investigate the long-run co-integrating relationships in the Asian markets. Our research focuses on 4 areas; pair trading, out-of-sample forecasting, testing the unbiased forward exchange rate hypothesis and testing the expectation hypothesis of the term structure of interest rates. The introduction is provided in chapter one. In chapter two, we develop a pairs trading strategy using individual stocks listed in the Stock Exchange of Thailand. Engle and Granger approach is used to identify the potential pairs that are cointegrated. The results show that pairs trading strategy is profitable in this market. Chapter three examines the forecasting performance of the error correction model on daily share price series from the Stock Exchange of Thailand. The disequilibrium term is classified into “correct” and “mix” sign based on Alexander (2008)’s criterion; the results indicate that the error correction component can help to improve the predictability in the long run. Chapter four tests the unbiased forward rate hypothesis of 11 Asian exchange rates using linear conventional regression, ECM and logistic smooth transition regression with the forward premium as the transition variable. Out-of-sample forecasting results also suggest that inferior forecasting performance could be obtained as a result of using linear models. In chapter five, we investigate the expectation hypothesis of the term structure of interest rate for four Asian countries. We employ linear models and nonlinear approaches that allow to capture asymmetric and symmetric adjustments. The result also indicates that the term structure can be better modeled by means of LSTR models. The forecasting exercise also confirms these findings.

Quantum information processing devices promise to solve some problems more efficiently than their classical counterparts. The source of the speedup is the structure of quantum theory itself. In that sense, the physical units that are the building blocks of such devices are its power. The quest then is to find or manufacture a system that behaves according to quantum theory, and yet is controllable in such a way that the desired algorithms can be implemented. Candidate systems are benchmarked against general criteria to evaluate their success. In this thesis, I advance a particular system and present the progress made towards each of these criteria. The system is a three-qubit 13C solid-state nuclear magnetic resonance (NMR) based quantum processor. I report results concerning system characterization and control, pseudopure state preparation, and quantum error correction. I also report on using the system to test a central question in the foundation of quantum mechanics.

Purpose: To retrospectively assess the incidence and predictive factors for self-correction of ectopic eruption of maxillary permanent first molars (EE) and the prevailing attitudes amongst surveyed specialists regarding intervention in cases of EE. Methods: Charts of patients diagnosed with EE were assessed for predictive clinical and radiographic factors. An online survey was sent to pediatric dentists and orthodontists. Results: The rate of self-correction was 71%. One third of self-corrections occurred after age 9. Increased amount of impaction (r(43)=0.59, p<.001) and degree of resorption (r(57)=0.41, p=.001) were positively correlated with irreversibility. Orthodontists estimated the spontaneous self-correction rate to be lower (t(1178)=19.2, p<.001) than pediatric dentists. Conclusions: One third of self-corrections occurred after 9 years of age and delaying treatment of EE may be a viable option when uncertain of the outcome. Reliable predictive factors of irreversibility of EE were identified. Differences exist between pediatric dentists and orthodontists regarding management of EE.